Michael invested $1,000 in large U.S. stocks at the beginning of 2012. This investment earned 17.90 percent in 2012, 32.00 percent in 2013, 13.50 percent in 2014, and 3.00 percent in 2015. What return did he earn in the average year during the 20122015 period? (Round answer to 2 decimal places, e.g. 1.52.)